Anaesthesia
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Randomized Controlled Trial Comparative Study
Effect of intra-operative pressure support vs pressure controlled ventilation on oxygenation and lung function in moderately obese adults.
Obesity impairs peri-operative lung function. To evaluate the impact of pressure support ventilation vs pressure controlled ventilation in moderately obese adults upon early postoperative lung function, we randomly assigned 68 moderately obese patients (body mass index 25-35 kg x m(-2)) undergoing minor surgery to receive intra-operative ventilation either with pressure support or pressure controlled ventilation. ⋯ Postoperatively, the pressure support ventilation group also had better lung function and oxygenation values than did the pressure controlled ventilation group (p < 0.005). We conclude that pressure support ventilation better maintains lung function than pressure controlled ventilation in moderately overweight patients scheduled for minor surgery.
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Comparative Study Controlled Clinical Trial
The effect of a new topical local anaesthetic delivery system on forearm skin blood flow reactivity.
Different topical local anaesthetics have varying effects on skin blood flow and vascular reactivity. We compared the vasoactive properties of Rapydan, a new topical local anaesthetic, with those of Ametop and EMLA creams in 20 healthy volunteers. ⋯ Application of EMLA had no effect on skin blood flow (median (IQR [range]) change from baseline -0.9% (-63 to 414 [-38.5 to 51.3] %, p = 1.0)) or mean (SD) transient hyperaemic response ratio (from 2.86 (0.86) to 3.17 (1.3), p = 0.38). The application of Ametop for 60 min produced a greater median (IQR [range]) increase in blood flow from baseline (508 (-55 to 998 [148-649]) %) than Rapydan applied for 30 min 160 (-77 to 997 [45-301]) %, p = 0.001), and a similar decrease in mean (SD) transient hyperaemic response ratio (from 2.69 (1.16) to 1.08 (0.26) and from 2.83 (0.84) to 1.49 (0.93) respectively, p = 0.57).
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Randomized Controlled Trial
The cardiovascular effects of normobaric hyperoxia in patients with heart rate fixed by permanent pacemaker.
To investigate whether the established reductions in heart rate and cardiac output with hyperoxia in humans are primary effects or secondary to increases in systemic vascular resistance, we paced the hearts of nine patients with permanent pacemakers at a fixed rate when breathing either medical air (inspired O(2) fraction 0.21) or oxygen (inspired O(2) fraction 0.80) in a randomised, double-blind fashion. A thoracic bio-impedance machine was used to measure heart rate, stroke volume and blood pressure and calculate cardiac index and systemic vascular resistance index. Oxygen caused no change in cardiac index (p = 0.18), stroke index (p = 0.44) or blood pressure (p = 0.52) but caused a small (5.5%) increase in systemic vascular resistance index (p = 0.03). This suggests that hyperoxia has no direct myocardial depressant effects, but that the changes in cardiac output reported in previous studies are secondary to changes in systemic vascular resistance.
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Recent trends in medical training have tended to focus on competence, in the sense of adequate performance, rather than excellence. This article reviews published literature and relevant concepts relating to excellence and professionalism from within anaesthesia, from medicine more generally and from outside the profession. A number of conceptual frameworks are presented that could be adapted for the promotion of excellence, and some of the necessary prerequisites for this promotion discussed.
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We investigated whether insertion of an LMA Supreme and its use for maintenance of anaesthesia is feasible in the prone position. Forty adult patients positioned themselves prone and were given propofol until the Bispectral Index was < 50. A size-4 LMA Supreme was inserted by experienced anaesthetists. ⋯ The frequency of blood staining and sore throat was 7.5% each. No other complications were noted. We conclude that use of the LMA Supreme in the prone position by experienced users is feasible.